A228647 a(n) = A001609(n^2) for n>=1, where g.f. of A001609 is x*(1+3*x^2)/(1-x-x^3).

1, 5, 31, 453, 14131, 946781, 136250983, 42115660581, 27961563559891, 39874307297033165, 122134599693975367423, 803522677430288749340325, 11354589189995520431547851761, 344634362031276605039944979868611, 22467750416780812361715214948922598721, 3146114090698891414621617889648190060326821

Offset

1,2

Comments

A001609 forms the logarithmic derivative of Narayana's cows sequence A000930.

Links

Table of n, a(n) for n=1..16.

Formula

Equals the logarithmic derivative of A228648.

Example

L.g.f.: L(x) = x + 5*x^2/2 + 31*x^3/3 + 453*x^4/4 + 14131*x^5/5 +...
where
exp(L(x)) = 1 + x + 3*x^2 + 13*x^3 + 128*x^4 + 2974*x^5 + 161048*x^6 + 19632276*x^7 +...+ A228648(n)*x^n +...

Prog

(PARI) {A001609(n)=n*polcoeff(-log(1-x-x^3 +x*O(x^n)), n)}
{a(n)=A001609(n^2)}
for(n=1, 20, print1(a(n), ", "))

Crossrefs

Cf. A218439, A228648, A001609, A000930, A231620.

Sequence in context: A307615 A020514 A201307 * A059301 A225158 A299887

Adjacent sequences: A228644 A228645 A228646 * A228648 A228649 A228650

Keyword

nonn

Author

Paul D. Hanna, Aug 28 2013

Status

approved